"The thing I have noticed is when the anecdotes and the data disagree, the anecdotes are usually right. There's something wrong with the way you are measuring it." - Jeff Bezos This is a tricky article because I can tell it's using the term 'exodus' and 'myth' differently than I would. It's abundantly clear there is a lot of migration out of California. Just ask Texans, Coloradans, and Idahoans.
As I've been chatting with some people at church* I was told that about 1/3 of the people that attend have moved to our little town in Idaho from Southern California in the past 2 years or so. That might not seem like much, but considering that this is small town in the middle of Idaho it seemed like a pretty big deal to me. It's especially interesting to see many people who have more traditional jobs, often revolving around construction or the cultivation of potatoes interacting with many of the white collar, MBA type Cali expats.
* Note: The church I attend is a world wide church and divides it's congregations based on geographic area, encouraging people to attend the service based on where they live. This point is made to forestall the correlation causation criticism, that would imply the church I attend is particularlye attractive to people that have recently moved in from SoCal,
EDIT: Just to clarify my wife and I did not move from Cali, we moved from Utah, because it was getting filled up with people from Cali, that resulted in prices for housing going up considerably.